06Ni_2．5CrMo焊缝横向氢致冷裂纹临界开裂方程

Critical Cracking Equation of Transverse Hydrogen -Induced-Cracking of 06Ni2.5CrMo Weld Metal

在对Ｇ－ＢＯＰ（ＧａｐｐｅｄＢｅａｄ－ｏｎ－ｐｌａｔｅ）试验进行系统研究的基础上，通过调整ＭＩＧ（Ｍｅｔａｌ－Ｉｎｅｒｔ－Ｇａｓ－Ｓｈｉｅｌｄｅｄ）焊保护气体露点，改变焊缝扩散氢含量，并测得０６Ｎｉ２．５ＣｒＭｏ焊缝的不同临界预热温度，进而通过回归分析得到了焊缝横向氢致冷裂纹临界开裂方程。试验结果表明，ＭＩＧ焊接时，提高保护气体露点，可使焊缝扩散氢含量增加，焊缝抗裂性能下降。利用Ｇ－ＢＯＰ试验方法，得到了临界预热温度和焊缝横向氢致冷裂纹临界开裂方程。该方程可指导焊接工艺的制定，预测焊缝冷裂纹敏感性及其临界开裂条件，具有重要的实际意义和独创性。

After an overall study on the characteristics of G-BOP(Gapped Bead-on-plate)test,the critical preheating temperature of transverse HIC in the 06Ni2.5CrMo weld has been obtained by changing the diffusible hydrogen content in weld metal through adjusting the dew temperature Tp of the shielding gas in MIG(Metal Inert-Gas-Shielded)welding. Then,the critical cracking equation of trans-verse HIC of 06Ni2.5CrMo weld metal has been gained by liner regression analysis. The results show that the diffusible hydrogen content in weld metal and the cracking susceptibility increase with the increase of Tp during MIG welding. The critical cracking equation as well as the critical preheating temperature of transverse HIC in weld metal can be obtained by G-BOP test.And it is of great importance to working out welding technology and predicting the cracking susceptibility and critical cracking condition of HIC in weld metal. This is proved to be creative.